ISS027-E-034398 (20 May 2011) --- NASA astronauts Andrew Feustel (left) and Greg Chamitoff, both STS-134 mission specialists, participate in the mission's first session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 19-minute spacewalk, Feustel and Chamitoff retrieved long-duration materials exposure experiments and installed another, installed a light on one of the station's rail line handcarts, made preparations for adding ammonia to a cooling loop and installed an antenna for the External Wireless Communication system.